Water filtration has become common in homes, offices and other places to produce cleaner and better tasting water. One popular filtration system is used in conjunction with a water pitcher. Some water pitchers include an upper chamber for holding untreated water and a lower chamber for holding treated water that has exited the upper chamber. A filter cartridge is placed in a fluid path between the two chambers so that untreated water exits the upper chamber through the filter cartridge and enters the lower chamber as filtered water.
The filter cartridge includes openings that allow unfiltered water to enter the interior of the filter cartridge where the unfiltered water comes into contact with a filtering medium that acts to remove contaminants from the water as the water flows through the interior of the filter cartridge. After filtering is completed, the filtered water exits the filter cartridge into the lower chamber. As a result, treated water is available and ready to be poured from the water pitcher for consumption by a user.
The filter cartridge typically resides in a receptacle defined by a candle that is located at the bottom of the upper chamber and that is open to both the upper and lower chambers. Absent the filter cartridge, water can flow from the upper chamber to the lower chamber by way of the candle. With proper alignment and seating of the filter cartridge within the candle, water can only flow from the upper chamber to the lower chamber through the filter cartridge. Typically, the filter cartridge is removable so that at the end of its useful life, the filter cartridge may be removed and replaced with a new filter cartridge.
Placement of the filter cartridge within the candle of the water pitcher is important for proper water treatment. In order to place the cartridge, the user typically must maneuver the filter cartridge so that the filter cartridge is properly aligned and firmly seated within the candle. If the filter cartridge is properly aligned and seated within the candle, a fluid tight seal, or substantially fluid tight seal, is formed between the candle and the exterior of the filter cartridge such that water can only flow from the upper chamber to the lower chamber through the filter cartridge.
In practice however, achievement of proper seating of the filter cartridge has proven problematic. This is due at least in part to the construction of typical water pitchers and, more particularly, the relation between various elements of the water pitcher.
For example, one problem is that proper alignment and seating of the filter cartridge in the candle requires focused effort on the part of the user. That is, proper alignment and seating of the filter cartridge generally cannot be achieved by simply dropping the filter cartridge into the candle. Instead, the user must perform an extra action to properly align the filter cartridge with respect to the candle, and then seat the filter cartridge within the candle.
In particular, after aligning the filter cartridge so that it can be received within the candle with the proper angular orientation, the user must also push the filter cartridge downward into the candle so that a fluid tight seal, or substantially fluid tight seal, is formed between the filter cartridge and the filter seat in the candle. Users often neglect to perform this necessary step and, as a result, the filter cartridge may be aligned but not properly seated, even though it can appear so to the user. This problem is further aggravated by the fact that typical filtration systems lack any sort of feedback mechanism that indicates to the user that the filter cartridge is properly seated.
Misalignment and/or improper seating of the filter cartridge, as described above, can present a variety of problems with respect to the operation of the filtration system. Among other things, misalignment and/or improper seating of the filter cartridge can result in a gap between the filter cartridge and the filter seat, thus allowing untreated water to bypass the interior of the filter cartridge and flow into the lower chamber, thereby introducing contaminants into the water held in the lower chamber.
Another problem with many filtration systems is that even if the filter cartridge is initially placed in the correct alignment and is properly seated in the candle, the filter cartridge may not be reliably retained in that position. For example, the filter cartridge can move out of position as a result of repeated use of the water pitcher, such as when the water pitcher is tipped to pour treated water from the lower chamber. That is, the tipping motion may act to change the position of the filter cartridge relative to the candle. Moreover, repeated tipping may also cause the filter cartridge to move partly, or completely, out of the candle.
In either case, the seal formed between the exterior of the filter cartridge and the candle has been compromised. Consequently, the next time the upper chamber is filled, untreated water can bypass the filter cartridge and flow directly into the lower chamber, thus contaminating the filtered water in the lower chamber.
Yet another concern with many filtration systems relates to the construction and placement of the filter cartridge. For example, filter cartridges often include a set of air vents at, or near, the top of the filter cartridge which allow air in the filter cartridge to escape as fluid flows into the filter cartridge. However, many filtration systems are constructed in such a way that as water is poured into the upper chamber, the incoming water directly impinges upon the air vents, effectively blocking the air vents and thus preventing the escape of air from the filter cartridge. Because air is prevented from escaping the filter cartridge, a static, or near static, condition results where water cannot easily enter the filter cartridge. This condition is sometimes referred to as airlock and slows the rate at which water flows through the filter cartridge.
A related problem that affects many filtration systems concerns the placement of the filter cartridge and the filtration media employed in the filter cartridge. For example, and as noted above, the filter cartridge is often located in a position where water entering the upper chamber impinges upon the filter cartridge air vents. As the inrushing water enters the air vents, the relatively high velocity of that water causes compaction of the filtration media within the filter cartridge. This compaction reduces the overall surface area available for filtration, thus reducing the effectiveness of the filtration media. Compacted filtration media also presents increased resistance to the fluid that is to be filtered, such that the fluid is not able to readily flow through the filtration media.
In light of problems such as those noted above, it would be useful to provide devices that ensure proper alignment and seating of a filter cartridge that is placed within a water pitcher. As well, it would be useful for the devices to be able to retain the filter cartridge in place, once properly positioned, during use of the pitcher, or other device, that includes the filter cartridge. Finally, it would be useful to avoid, or at least reduce, airlock of the filter cartridge, and media compaction.